WASHINGTON – Japan has built an earthquake early warning system that alerts people throughout the country before the earth begins to shake. Mexico, China, Romania and Turkey have created similar systems for some of the most quake-prone regions.

But the United States has no such system.

Even though a prototype has been tested for the past two years in California and the technology is almost ready to be deployed on a larger scale, advocates say Congress hasn’t provided the funding because it has simply not been a priority.

“We are sure there will be such a system after a big earthquake. We would like to do it before a big earthquake,” said Doug Given, head of the U.S. Geological Survey’s Southern California Earthquake Monitoring project in Pasadena.

Advocates are pressuring Congress to pay for a system that will warn people minutes or seconds before earthquakes occur. They say even such short notice will save countless lives and prevent billions of dollars in property losses.

They want Congress to expand ShakeAlert, a 2-year-old program that sends trial alerts to a handful of government agencies and companies in California. The national system should go live first in California, Oregon and Washington – where 71 percent of the nation’s earthquakes occur – and then expand into the rest of the country in phases, Given said.

Southern California alone experiences about 10,000 quakes in a year, though virtually all of them are minor tremors.

A state law adopted last year requires California to establish a statewide early alert system. But Given said that effort relies on the scaled up ShakeAlert model.

Given, coordinator of the ShakeAlert test program, said scientists are good at detecting quakes as they occur using the California Integrated Seismic Network. But the network’s monitoring “stations,” located throughout California, can be easily upgraded to predict when and where the next quake will occur, he said.

All that’s required is a network of slightly more sophisticated sensors buried at least 8 feet underground up and down the West Coast – 400 additional stations in California and 100 in Washington and Oregon combined, Given said in a recent interview.

Such a system is especially critical in California because it has a 99.7 percent chance of experiencing a severe earthquake – magnitude 6.7 or higher on the Richter scale – within the next 30 years, according William Leith, a science adviser for the Geological Survey, who testified earlier this month before a House Natural Resources subcommittee.

The Geological Survey estimates it would need $38 million initially to get a land-based early warning system up and running on the West Coast and $16 million a year to run it. That’s a modest sum as far as federal programs go and far less than the $600 million Japan spent on its national system.

However, that doesn’t include deploying underwater censors off the Pacific Northwest or the costs of developing and disseminating the alerts.

The alerts would give people a precious few seconds – or a few minutes in the best-case scenario – to take cover before the ground beneath their feet starts to shake, advocates say. A few other benefits: Authorities could stop trains, close the valves on oil and gas pipelines and shut down nuclear reactors when the alarms sound.

Advocates envision warnings going out over the emergency broadcast system, cellular networks and the Internet, so people get text alerts like they do for adverse weather and missing children. But those arrangements are far from complete. Given said officials are also working on smaller but equally crucial details like what the alerts should say and what tone should be used so people can distinguish quake warnings from other types of emergencies. The government also hasn’t talked to private companies to make sure the alerts go out on Twitter, Facebook and other social media.

However, advocates say, the important thing is that the sensors can now predict quakes, not just monitor them after the fact.

Richard Allen, director of the University of California’s Berkeley Seismological Lab, told the House subcommittee that ShakeAlert will be ready for prime time in two years once Congress releases the first funding installment.

ShakeAlert issued a warning 40 seconds before last year’s Anza earthquake near Los Angeles and 24 seconds ahead of a small tremor in the vicinity of the 1989 Loma Prieta quake, which killed 63 people and injured nearly 3,800 others in the San Francisco and Monterey Bay areas, Allen said.

“Investing in this system now will provide fast, accurate and robust warnings,” he said. “The earthquake threat along the U.S. west coast increases every day as the strain builds on our faults.”